1. Field of the Invention
The present invention relates to a vehicle-body structure for a motorcycle.
2. Description of Background Art
A vehicle, for example a motorcycle, is known that includes a function of absorbing a load at an application of excessive load from the front of the vehicle. More specifically, a front portion of a vehicle-body frame is formed in a shape like a bow of a ship with the front portion being positioned behind a front wheel. Further, the tip of the bow is offset to the right or the left from the center line, in the width direction, of the front wheel of the motorcycle maintained in the state of traveling straight. See, for example, Japanese Patent Application Publication No. 2002-264866.
In such a motorcycle, when the front wheel is deformed to the front portion of the vehicle-body frame at the application of excessive load from the front of the vehicle, the offset-tip of the bow deflects the front wheel from the vehicle-body frame so that the front wheel is deformed sufficiently. As a result, the excessive load is smoothly absorbed since interference between the front wheel and the vehicle-body frame is prevented.
According to Japanese Patent Application Publication No. 2002-264866, the excessive load applied from the front of the vehicle can be absorbed when the motorcycle is traveling straight. However, in a case where an excessive load is applied when the front wheel is steered to the side opposite to that to which the tip of the bow is offset, the load is applied to the tip of the bow, and a forward rotating behavior of the vehicle body may not be suppressed sufficiently. More specifically, consider a case where the load received by the front wheel is applied to the vehicle-body frame. In this case, when the vehicle body and the colliding object move away from each other due to reaction after the application of the excessive load, a remaining moment of the vehicle-body frame may cause reduction of the contact load of the rear wheel.